SU-E-T-563: Applicability of Image Smoothing for Dose Calculation of High Density Phantoms in Patient Specific Delivery Quality Assurance

2011 ◽  
Vol 38 (6Part19) ◽  
pp. 3619-3619
Author(s):  
A Kakakhel ◽  
M Snyder ◽  
D Lack
2019 ◽  
Vol 9 ◽  
Author(s):  
Jae Hyuk Choi ◽  
Danny Lee ◽  
Laura O'Connor ◽  
Stephan Chalup ◽  
James S. Welsh ◽  
...  

2020 ◽  
Vol 4 (s1) ◽  
pp. 106-106
Author(s):  
Holly Marie Parenica ◽  
Christopher Kabat ◽  
Pamela Myers ◽  
Neil Kirby ◽  
Pavlos Papaconstadopoulos ◽  
...  

OBJECTIVES/GOALS: The Monte Carlo dose calculation method is often considered the “gold standard” for patient dose calculations and can be as radiation dose measurements. Our study aims to develop a true Monte Carlo model that can be implemented in our clinic as part of our routine patient-specific quality assurance. METHODS/STUDY POPULATION: We have configured and validated a model of one of our linear accelerators used for radiation therapy treatments using the EGSnrc Monte Carlo simulation software. Measured dosimetric data was obtained from the linear accelerator and was used as the standard to compare the doses calculated with our model in EGSnrc. We will compare dose calculations between commercial treatment planning systems, the EGSnrc Monte Carlo model, and patient-specific measurements. We will implement the Monte Carlo model in our clinic for routine second-checks of patient plans, and to recalculate plans delivered to patients using machine log files. RESULTS/ANTICIPATED RESULTS: Our Monte Carlo model is within 1% agreement with our measured dosimetric data, and is an accurate representation of our linear accelerators used for patient treatments. With this high level of accuracy, we have begun simulating more complex patient treatment geometries, and expect the level of accuracy to be within 1% of measured data. We believe the Monte Carlo calculation based on machine log files will correlate with patient-specific QA analysis and results. The Monte Carlo model will be a useful tool in improving our patient-specific quality assurance protocol and can be utilized in further research. DISCUSSION/SIGNIFICANCE OF IMPACT: This work can be implemented directly in clinical practice to ensure patient doses are calculated as accurately as possible. These methods can be used by clinics who do not have access to more advanced dose calculation software, ensuring accuracy for all patients undergoing radiotherapy treatments.


2020 ◽  
Vol 150 ◽  
pp. 136-141
Author(s):  
Arturs Meijers ◽  
Gabriel Guterres Marmitt ◽  
Kelvin Ng Wei Siang ◽  
Arjen van der Schaaf ◽  
Antje C. Knopf ◽  
...  

2020 ◽  
Vol 93 (1107) ◽  
pp. 20190669 ◽  
Author(s):  
Mei Chen ◽  
Pablo Yepes ◽  
Yoshifumi Hojo ◽  
Falk Poenisch ◽  
Yupeng Li ◽  
...  

Objective: This study is part of ongoing efforts aiming to transit from measurement-based to combined patient-specific quality assurance (PSQA) in intensity-modulated proton therapy (IMPT). A Monte Carlo (MC) dose-calculation algorithm is used to improve the independent dose calculation and to reveal the beam modeling deficiency of the analytical pencil beam (PB) algorithm. Methods: A set of representative clinical IMPT plans with suboptimal PSQA results were reviewed. Verification plans were recalculated using an MC algorithm developed in-house. Agreements of PB and MC calculations with measurements that quantified by the γ passing rate were compared. Results: The percentage of dose planes that met the clinical criteria for PSQA (>90% γ passing rate using 3%/3 mm criteria) increased from 71.40% in the original PB calculation to 95.14% in the MC recalculation. For fields without beam modifiers, nearly 100% of the dose planes exceeded the 95% γ passing rate threshold using the MC algorithm. The model deficiencies of the PB algorithm were found in the proximal and distal regions of the SOBP, where MC recalculation improved the γ passing rate by 11.27% (p < 0.001) and 16.80% (p < 0.001), respectively. Conclusions: The MC algorithm substantially improved the γ passing rate for IMPT PSQA. Improved modeling of beam modifiers would enable the use of the MC algorithm for independent dose calculation, completely replacing additional depth measurements in IMPT PSQA program. For current users of the PB algorithm, further improving the long-tail modeling or using MC simulation to generate the dose correction factor is necessary. Advances in knowledge: We justified a change in clinical practice to achieve efficient combined PSQA in IMPT by using the MC algorithm that was experimentally validated in almost all the clinical scenarios in our center. Deficiencies in beam modeling of the current PB algorithm were identified and solutions to improve its dose-calculation accuracy were provided.


2013 ◽  
Vol 40 (12) ◽  
pp. 121708 ◽  
Author(s):  
Dennis Mackin ◽  
Yupeng Li ◽  
Michael B. Taylor ◽  
Matthew Kerr ◽  
Charles Holmes ◽  
...  

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