Investigation of Leakage and Transmission Radiation through the MLC Version I2 Applied To the Elekta Synergy 6 MV Photon Beam Linac

Document Type : Original Paper

Authors

1 LPMR, Faculty of sciences, University Mohamed 1st, Oujda, Moroccco.

2 National School of Applied Sciences, University Mohamed 1st, Oujda, Morocco

3 LPMR, Faculty of sciences, University Mohamed 1st, Oujda, Morocco

4 LPMR, Faculty of sciences, University Mohamed 1st, Oujda, Morocco.

Abstract

Introduction: Radiotherapy and nuclear medicine extensively use Monte Carlo simulation to study particle transport and interactions. The aim of this task is the investigation and simulation of leakage and transmission (L&T) particles using the Multi-Leaf Collimator version i2 applied to the Elekta Synergy linac.
Material and Methods: In this study, all linac segments are included in the simulation model. In order to reduce MC calculation time, the new HPC-Slurm cluster platform and the Python phase space approach are used. To study the transmission between MLCi2 leaves, a detailed analysis of the dose distribution was conducted.
Results: The simulation results obtained with Gate 9.0 MC are excellently correlated with the measured data with error estimates for the 6 MV photon beam parameters less than 1% and a validation level of 99% in terms of the gamma index's (2%/2mm) threshold formalism for the cross profiles and PDD's dose distributions. The results indicate that contamination particles (e-, e+) have an effect on the distribution of dose in the patient. These particles are present in the beam produced previously and which is assumed to contain only X-rays. In addition, a three-dimensional distribution of dose inside the tumor (CT-scan) confirms the L&T effect of the studied version of the multi leaf collimator (MLCi2), with a dose range of around 70% of the delivered dose to the tumor, resulting in secondary outcomes at the DNA.
Conclusion: Consequently, the production of a new generation of MLC that can limit this L&T effect should be encouraged.

Keywords

Main Subjects

References

  1. Zheng Y, Qiu Y, Lu P, Chen Y, Fischer U, Liu S. An improved on-the-fly global variance reduction technique by automatically updating weight window values for Monte Carlo shielding calculation. Fusion Engineering and Design. 2019 Oct 1;147:111238.
  2. Lárraga-Gutiérrez JM, de la Cruz OG, García-Garduño OA, Ballesteros-Zebadúa P. Comparative analysis of several detectors for the measurement of radiation transmission and leakage from a multileaf collimator. Physica Medica. 2014 May 1;30(3):391-5.
  3. Krim DE, Rrhioua A, Zerfaoui M, Bakari D, Oulhouq Y, Bouta M. Simulation of the patient-dependent part 6 MV Elekta linac photon beam using GATE. In2019 International Conference on Intelligent Systems and Advanced Computing Sciences (ISACS). 2019 : 1-6. IEEE. Doi: 10.1109/ISACS48493.2019.9068922.
  4. Gardner M, McNabb A, Seppi K. A speculative approach to parallelization in particle swarm optimization. Swarm Intelligence. 2012 Jun;6(2):77-116.
  5. Kim JO, Siebers JV, Keall PJ, Arnfield MR, Mohan R. A Monte Carlo study of radiation transport through multileaf collimators. Medical physics. 2001 Dec;28(12):2497-506.
  6. Arnfield MR, Siebers JV, Kim JO, Wu Q, Keall PJ, Mohan R. A method for determining multileaf collimator transmission and scatter for dynamic intensity modulated radiotherapy. Medical physics. 2000 Oct;27(10):2231-41.
  7. Li J, Zhang XZ, Gui LG, Zhang J, Tang XB, Ge Y, et al. Clinical feasibility of leakage and transmission radiation dosimetry using multileaf collimator of ELEKTA synergy-S accelerator during conventional radiotherapy. Journal of Medical Imaging and Health Informatics. 2016 Apr 1;6(2):409-15.
  8. Almond PR, Biggs PJ, Coursey BM, Hanson WF, Huq MS, Nath R, et al. AAPM's TG‐51 protocol for clinical reference dosimetry of high‐energy photon and electron beams. Medical physics. 1999 Sep;26(9):1847-70.
  9. Sanz DE, Alvarez GD, Nelli FE. Ecliptic method for the determination of backscatter into the beam monitor chambers in photon beams of medical accelerators. Physics in Medicine & Biology. 2007 Feb 26;52(6):1647.
  10. Papadimitroulas P. Dosimetry applications in GATE Monte Carlo toolkit. Physica Medica. 2017 Sep 1;41:136-40.
  11. Antcheva I, Ballintijn M, Bellenot B, Biskup M, Brun R, Buncic N, et al. ROOT—A C++ framework for petabyte data storage, statistical analysis and visualization. Computer Physics Communications. 2009 Dec 1;180(12):2499-512.
  12. Agostinelli S, Allison J, Amako KA. Apostolakis, & Geant4 Collaboration. GEANT4—a simulation toolkit. Nucl Instrum Methods Phys Res. 2003;506(3):250-303.
  13. Low DA, Dempsey JF. Evaluation of the gamma dose distribution comparison method. Medical physics. 2003 Sep;30(9):2455-64.
  14. Van Dyk J, Barnett RB, Cygler JE, Shragge PC. Commissioning and quality assurance of treatment planning computers. International Journal of Radiation Oncology* Biology* Physics. 1993 May 20;26(2):261-73.
  15. Krim DE, Rrhioua A, Zerfaoui M, Bakari D. Development of a new Hybrid Virtual Source Model to simulate Elekta Synergy MLCi2 linac. Radiation Measurements. 2022 May 20:106780.
  16. HPC-Marwan. 2018. Available from: www.marwan.ma/index.php/services/hpc.
  17. Krim DE, Rrhioua A, Zerfaoui M, Bakari D, Hanouf N. GATE Simulation of 6 MV Photon Beam Produced by Elekta Medical Linear Accelerator. InInternational Conference on Electronic Engineering and Renewable Energy. 2020: 301-7.
  18. Krim DE, Bakari D, Zerfaoui M, Rrhioua A. Implementation of a new virtual source model in Gate 9.0 package to simulate Elekta Synergy MLCi2 6 MV accelerator. Biomedical Physics & Engineering Express. 2021 Jul 8;7(5):055004.
  19. Musolino SV. Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose to water. technical reports series. 2001;398.
  20. Sheikh‐Bagheri D, Rogers DW. Monte Carlo calculation of nine megavoltage photon beam spectra using the BEAM code. Medical physics. 2002 Mar;29(3):391-402.
  21. Kantz S, Söhn M, Troeller A, Reiner M, Weingandt H, Alber M, et al. Impact of MLC properties and IMRT technique in meningioma and head-and-neck treatments. Radiation Oncology. 2015 Dec;10(1):1-5.
  22. Sarrut D, Bardiès M, Boussion N, Freud N, Jan S, Létang JM, et al. A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications. Medical physics. 2014 Jun;41(6Part1):064301.

 

 

 

 

 

Iranian Journal of Medical Physics
Volume 19, Issue 6
November and December 2022
Pages 334-345

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History

  • Receive Date: 23 December 2021
  • Revise Date: 23 March 2022
  • Accept Date: 05 April 2022

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