A sliding-window approach for improved VMAT dose calculation accuracy
The continuous delivery of volumetric modulated arc therapy (VMAT) plans is usually approximated by discrete apertures at evenly-spaced gantry angles for dose calculation purposes. This approximation can potentially lead to large dose calculation errors if the gantry angle spacings are large and/or there are large changes in the MLC apertures from one control point (CP) to the next. In this work, we developed a sliding-window (SW) method to improve VMAT dose calculation accuracy. For any 2 adjacent VMAT CPs ni and ni + 1, the dose distribution was approximated by a 2-CP SW IMRT beam with the starting MLC positions at CP ni and ending MLC positions at CP ni + 1, with the gantry angle fixed in the middle of the 2 VMAT CPs.
Source: Medical Dosimetry - Category: Radiology Authors: Haitham N Alahmad, Ji-Yeon Park, Nicholas J Potter, Bo Lu, Guanghua Yan, Chihray Liu, Jonathan G Li Source Type: research
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