Portal Dosimetry for Pre-treatment Verification of Imrt/Vmat Plan: A Comparison with 2D Array Detector for Quality Assurance

Mohamed, Ayman G; Mohamed, Ismail E.; Zidan, H. M.

doi:10.4172/2155-9619.1000359

Cited by 2 publications

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“…IMRT QA is commonly accomplished by comparing a calculated dose distribution with an actually measured dose distribution (7,8) . Various methods, including the use of electronic portal imaging device (EPID), Epiqa software using GLAaS algorithm and 2D Array detectors have been employed during patient-specific QA in pretreatment verification to detect possible errors between the dose calculated by the TPS and the measured dose (9,10,11) . IMRT programs today almost universally use some method of quantitative comparison between TPS planar dose and measured dose, generating statistics of calculations such as percentage difference, distance to agreement (DTA), and gamma analysis (12) .…”

Section: Introductionmentioning

confidence: 99%

The impacts of dose rate in sliding window intensity modulated radiation therapy quality assurance

Gül

İNAN

2021

Int J Radiat Res

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Background:The present study aims to compare the impacts of dose rate in intensity-modulated radiation therapy (IMRT) plan delivery by using the gamma agreement between the calculated and measured doses by pretreatment quality assurance (QA). Materials and Methods: Ten nasopharynx cancer patients who underwent IMRT treatment were included in this study. The treatment plans were performed using Varian DHX eclipse treatment planning system (TPS) version 15.1. and the QA plans were generated for the dose rates of 300, 400, 500 and 600 MU/min. All measurements were performed by aS1000 Electronic Portal Imaging Device (Epid) integrated into Varian DHX linear accelerator and 2D array detector. The dose distribution was evaluated with gamma area histograms (GAHs) generated using different γ criteria (2%/2 mm and 3%/3 mm) for dose agreement and distance to agreement parameters. Statistical analyses were evaluated by using Mann-Whitney Test and a p-value of p <0.05 was considered to be significant. Results: There was a significant decrease in the percentage gamma pass rate when the dose rate was increased from 300 MU/min to 600 MU/min (p<0.05). There was a significant difference between Epid and Epiqa for all dose rates (p<0.05). The total number of MU was correlated to the dose rate. When comparing MU from 300 MU/min to 600 MU/min dose rate, it was observed that the MU of IMRT plans increaed as the dose rate was increased. Conclusion: In this study, we have demonstrated that IMRT delivery using sliding window method is affected by the dose rate.

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Section: Introductionmentioning

confidence: 99%

The impacts of dose rate in sliding window intensity modulated radiation therapy quality assurance

Gül

İNAN

2021

Int J Radiat Res

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Comparison of gamma analysis with using different dosimetric systems for pre-treatment verification of intensity-modulated radiation therapy

Inan

Gül

2021

Can. J. Phys.

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Purpose: The evaluation of the agreement between calculated and measured dose plays an essential role in the quality assurance (QA) procedures of intensity-modulated radiation therapy (IMRT). This study aimed to compare gamma analysis using Portal Dosimetry (PD), Epiqa, and 2D array detector for dose verification of radiotherapy treatment plans. Materials and Methods: Five fields step-and-shoot IMRT plan was used to performed for 20 prostate IMRT patients using the dual-energy DHX linear accelerator (Varian Medical System, Palo Alto, CA, USA). The treatment plans were created using Varian DHX Eclipse treatment planning system (TPS) version 15.1. All measurements were performed by aS500 EPID integrated into Varian DHX linear accelerator and 2D array detector. The dose distribution was evaluated with gamma area histograms (GAHs) generated using different γ criteria (1%/1 mm, 2%/2 mm 3%/2 mm and 3%/3 mm) for dose agreement and distance to agreement parameters. Statistical analyses were evaluated by using Mann Whitney Test and Kruskal-Wallis Test, and p-value of p <0.01 was considered to be significant. Results: The average pass rate for 20 IMRT plans was above 95% for all devices with 2%/2 mm, 3%/2 mm and 3%/3 mm. The mean and standard deviation passing rates (γ ≤1) were found to be 99.80±0.19, 99.35±0.34 and 97.53±0.71 for PD, Epiqa and 2D array respectively. All IMRT plans passed 2%/2 mm, 3%/2 mm and 3%/3 mm gamma by more than 95% of three dosimetric systems. They are all in good agreement with the literature. Conclusion: All three devices are acceptable for quality control of IMRT. Due to the simplicity and fast evaluation process, PD can be preferred for quality control.

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Portal Dosimetry for Pre-treatment Verification of Imrt/Vmat Plan: A Comparison with 2D Array Detector for Quality Assurance

Cited by 2 publications

References 0 publications

The impacts of dose rate in sliding window intensity modulated radiation therapy quality assurance

The impacts of dose rate in sliding window intensity modulated radiation therapy quality assurance

Comparison of gamma analysis with using different dosimetric systems for pre-treatment verification of intensity-modulated radiation therapy

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