Highlights
- •A Monte Carlo model of linear accelerator head was created and Validated.
- •Dosimetry comparisons of MC with Monaco treatment planning system were done for 40 SBRT patients of various cancer types.
- •Proof the visibility of using Monte Carlo as a quality control tool of the patient’s dosimetry.
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.
Keywords
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Article info
Publication history
Published online: March 23, 2021
Accepted:
February 24,
2021
Received in revised form:
January 20,
2021
Received:
August 28,
2020
Identification
Copyright
© 2021 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.
