scholarly journals Study of out‐of‐field dose in photon radiotherapy: A commercial treatment planning system versus measurements and Monte Carlo simulations

2020 ◽  
Vol 47 (9) ◽  
pp. 4616-4625 ◽  
Author(s):  
B. Sánchez‐Nieto ◽  
K. N. Medina‐Ascanio ◽  
J. L. Rodríguez‐Mongua ◽  
E. Doerner ◽  
I. Espinoza
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Treatment Planning ◽  
Planning System ◽  
Treatment Planning System ◽  
System Versus ◽  
Photon Radiotherapy

scholarly journals Experimental Validation of Monte Carlo Simulations Based on a Virtual Source Model for TomoTherapy in a RANDO Phantom

2016 ◽  
Vol 15 (6) ◽  
pp. 796-804
Author(s):  
Jiankui Yuan ◽  
Yiran Zheng ◽  
Barry Wessels ◽  
Simon S. Lo ◽  
Rodney Ellis ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Treatment Planning ◽  
Helical Tomotherapy ◽  
Source Model ◽  
Planning System ◽  
Treatment Planning System ◽  
Virtual Source ◽  
Passing Rate ◽  
Accurate Dose

A virtual source model for Monte Carlo simulations of helical TomoTherapy has been developed previously by the authors. The purpose of this work is to perform experiments in an anthropomorphic (RANDO) phantom with the same order of complexity as in clinical treatments to validate the virtual source model to be used for quality assurance secondary check on TomoTherapy patient planning dose. Helical TomoTherapy involves complex delivery pattern with irregular beam apertures and couch movement during irradiation. Monte Carlo simulation, as the most accurate dose algorithm, is desirable in radiation dosimetry. Current Monte Carlo simulations for helical TomoTherapy adopt the full Monte Carlo model, which includes detailed modeling of individual machine component, and thus, large phase space files are required at different scoring planes. As an alternative approach, we developed a virtual source model without using the large phase space files for the patient dose calculations previously. In this work, we apply the simulation system to recompute the patient doses, which were generated by the treatment planning system in an anthropomorphic phantom to mimic the real patient treatments. We performed thermoluminescence dosimeter point dose and film measurements to compare with Monte Carlo results. Thermoluminescence dosimeter measurements show that the relative difference in both Monte Carlo and treatment planning system is within 3%, with the largest difference less than 5% for both the test plans. The film measurements demonstrated 85.7% and 98.4% passing rate using the 3 mm/3% acceptance criterion for the head and neck and lung cases, respectively. Over 95% passing rate is achieved if 4 mm/4% criterion is applied. For the dose–volume histograms, very good agreement is obtained between the Monte Carlo and treatment planning system method for both cases. The experimental results demonstrate that the virtual source model Monte Carlo system can be a viable option for the accurate dose calculation of helical TomoTherapy.

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