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


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.


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.


Main Subjects

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Volume 19, Issue 6
November and December 2022
Pages 334-345
  • Receive Date: 23 December 2021
  • Revise Date: 23 March 2022
  • Accept Date: 05 April 2022