Abstract
PurposeCheckTomo is an independent dose calculation software for tomotherapy. Recently, Accuray (Accuray Inc., Sunnyvale, CA, USA) released an upgrade of its tomotherapy treatment device, called TomoEDGE Dynamic Jaws, which improves the quality of treatment plans by enhancing the dose delivery with the help of jaws motion. This study describes the upgrade of CheckTomo to that new feature.MethodsTo account for the varying width and off‐axis shift of dynamic jaws fields, the calculation engine of CheckTomo multiplies the treatment field profile by a penumbral filter and shifts the dose calculation grid. Penumbral filters were obtained by dividing the edge field profiles by that of the corresponding nominal field. They were sampled at widths 1.0, 1.8, and 2.5 cm at isocenter in the edges of the 2.5 and 5 cm treatment field.ResultsThe upgrade of CheckTomo was tested on 30 patient treatments planned with dynamic jaws. The gamma pass rate averaged over 10 abdomen plans was 95.9%, with tolerances of 3 mm/3%. For 10 head and neck plans, the mean pass rate was 95.9% for tolerances of 4 mm/4%. Finally, misplacement and overdosage errors were simulated. In each tested cases, the 2 mm/3% gamma pass rate fell below 95% when a 4 mm shift or 3% dose difference was applied.ConclusionsThese results are equivalent to what CheckTomo achieves in static jaws cases. So, in terms of dose calculation accuracy and errors detection, the upgraded version of CheckTomo is as reliable for dynamic jaws plans as the former release was for static cases.
Highlights
Independent dose verification is considered to be important to ensure patient safety.[1]
An open source solution, CheckTomo, was released in 2011.3 That software independently generates a three-dimensional point-based dose distribution, using patient CT images and delivery plan, and compares it against the dose volume calculated by the tomotherapy treatment planning system (TPS)
Note that Eq (3) yields a symmetric approximation of the edge field profiles, which are asymmetric
Summary
Independent dose verification is considered to be important to ensure patient safety.[1] It can be performed through an independent calculation with commercial softwares for three-dimensional conformal radiation therapy (3DCRT), image-modulated radiation therapy (IMRT), and volume-modulated arc therapy (VMAT) treatments. As far as we know, there exists a commercial tool, Mobius 3D (Mobius Medical Systems, Houston, TX, USA), and a single-point dose verification software.[2] an open source solution, CheckTomo, was released in 2011.3 That software independently generates a three-dimensional point-based dose distribution, using patient CT images and delivery plan, and compares it against the dose volume calculated by the tomotherapy treatment planning system (TPS). The way the dose is delivered is modified and the dose calculation engine of CheckTomo needed to be upgraded
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