The aims of the research are to determine the detectability and dosimetric impact of control point variation in volumetric arc radiotherapy treatments, adding to the existing knowledge of the effects of discrepancies in IMRT delivery. A number of different delivery error types will be simulated for a range of clinical plans, including control point variations in gantry, collimator, couch angle, and MLC variation, both random and systematic. The error dependence on the gantry position will also be investigated, along with a consideration of the fully dynamic nature of modern treatment delivery with error in all moving components.
The detectability of variations will be determined using the Delta4 3D diode array. Once the threshold of detectability has been established, the clinical significance of the deviations will be determined by recalculating the simulated plans in the Eclipse treatment planning system using dose volume histogram (DVH) and/or equivalent uniform dose (EUD) methodologies.
Project still in progress.