Abstract
Purpose: The purpose of this study is to investigate the dosimetric effects of the beam delivery system on the delivered dose distributions of RapidArc treatments and their impact on RapidArc patient‐specific quality assurance. Methods: Monte Carlo dose calculations based on intensity maps that were built from the actual deliverable leaf sequences with and without considering the characteristics of the beam delivery system were performed in this study using our in‐house Monte Carlo software. The resolution of the intensity map is 0.2×0.2mm2 at the isocenter plane. The characteristics studied in this work include the source distribution, MLC leaf thickness, leakage, tongue‐and‐groove structure, effective leaf offset and dynamic delivery. The mean dose of the treatment target volume and the voxel doses in the high dose region of 5 RapidArc plans were used for comparison and evaluation. Results: The extra‐focal source, MLC leaf thickness, leakage, tongue‐and‐groove structure, effective leaf offset and dynamic delivery can affect the mean dose of a RapidArc treatment by up to 1.0%, 4.8%, 3.2%, 6.7%, 9.4% and 0.4%, respectively, when these factors are considered separately. They also cause significant uncertainties to the voxel dose with standard deviations up to 1.0%, 0.6%, 0.2%, 1.0%, 1.6% and 1.1%, respectively. The overall effect of all these characteristics on the mean dose is up to 2.2% and the standard deviation of the voxel dose uncertainty is up to 1.8%. The maximum voxel dose difference caused by these factors is up to 7.6%, 6.5%, 4.8%, 11.5%, 16.8% and 21.5% in the high dose region. Conclusions: The characteristics of the beam delivery system have great contribution to point dose uncertainty of a RapidArc treatment. And the effects are case‐dependent and location‐dependent. Treatment planning system should consider all these effects more precisely in the final dose calculation to reduce the measured dose uncertainty.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
