[Optimization of multi-leaf collimator leaf offset table for a treatment planning system].

For accurate dose delivery using a rounded leaf-end multi-leaf collimator (MLC), a consistent understanding of MLC leaf offset is required between a linear accelerator (linac) controller and a treatment planning system (TPS). We have found that the leaf offset tables were inconsistent between an Elekta linac controller and a Pinnacle TPS. An optimum leaf offset table for Pinnacle was determined by operating the TPS and the linac controller. It was suggested that the MLC leaf transmission value and the MLC leaf offset table stored in Pinnacle may need to be revised to improve dose verification results for volumetric modulated arc therapy.