Beam modeling and VMAT performance with the Agility 160-leaf multileaf collimator
Autor: | G. Smyth, Michael D. R. Thomas, James L. Bedford |
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Rok vydání: | 2013 |
Předmět: |
Computer science
multileaf collimator dose calculation Sensitivity and Specificity Planned Dose Radiation oncology Radiation Oncology Physics Humans Arc therapy Radiology Nuclear Medicine and imaging volumetric‐modulated arc therapy Radiometry Radiation treatment planning Instrumentation Radiation business.industry Radiotherapy Planning Computer-Assisted Reproducibility of Results Isocenter Radiotherapy Dosage Equipment Design Volumetric modulated arc therapy Equipment Failure Analysis Multileaf collimator Head and Neck Neoplasms Radiotherapy Intensity-Modulated treatment planning system Dose rate Nuclear medicine business Biomedical engineering |
Zdroj: | Journal of Applied Clinical Medical Physics |
ISSN: | 1526-9914 |
DOI: | 10.1120/jacmp.v14i2.4136 |
Popis: | The Agility multileaf collimator (Elekta AB, Stockholm, Sweden) has 160 leaves of projected width 0.5 cm at the isocenter, with maximum leaf speed 3.5cms−1. These characteristics promise to facilitate fast and accurate delivery of radiotherapy, particularly volumetric‐modulated arc therapy (VMAT). The aim of this study is therefore to create a beam model for the Pinnacle3 treatment planning system (Philips Radiation Oncology Systems, Fitchburg, WI), and to use this beam model to explore the performance of the Agility MLC in delivery of VMAT. A 6 MV beam model was created and verified by measuring doses under irregularly shaped fields. VMAT treatment plans for five typical head‐and‐neck patients were created using the beam model and delivered using both binned and continuously variable dose rate (CVDR). Results were compared with those for an MLCi unit without CVDR. The beam model has similar parameters to those of an MLCi model, with interleaf leakage of only 0.2%. The verification of irregular fields shows a mean agreement between measured and planned dose of 1.3% (planned dose higher). The Agility VMAT head‐and‐neck plans show equivalent plan quality and delivery accuracy to those for an MLCi unit, with 95% of verification measurements within 3% and 3 mm of planned dose. Mean delivery time is 133 s with the Agility head and CVDR, 171 s without CVDR, and 282 s with an MLCi unit. Pinnacle3 has therefore been shown to model the Agility MLC accurately, and to provide accurate VMAT treatment plans which can be delivered significantly faster with Agility than with an MLCi. PACS number: 87.55kd, 87.55km, 87.56bd, 87.56jk |
Databáze: | OpenAIRE |
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