Forecasting of the composite dose for organs at risk and solid targets with random movements during different image-guided scenarios of the photon radiation therapy. Solution for the Varian therapeutic line.

Abstract

BackgroundThis study aims to develop a useful tool for robust plan analysis which includes the effects of soft tissue deformations on simulated dose distributions. The solution was benchmarked in the light of the commercial method implemented in EclipseTM treatment planning system (TPS).Materials and methodsStudy was carried out on data of one patient with prostate-restricted cancer. The workflow of the procedure developed focused on three executive elements: in-house script to create a set of artificial CT images and for movement simulation of the CT V; the VelocityTM software for the calculations of the deformation matrixes and, then, to generate deformed CT sets; the EclipseTM TPS for dose re-calculations and analysis. Two scenarios were examined — first when the recalculation was done for the original geometry and second, when the isocentre from the original plan geometry was moved according to the movement of the CT V. The dose distributions were analysed on dose volume histograms (DVHs) in the light of the results obtained from the method implemented in the EclipseTM TPS.ResultsThe DVHs from our methods are more informative than the DVH from commercially implemented tools. For the first scenario, the highest impact on dose uncertainty has boundary positions of the CT V to the CT V-PTV margin. Using the second scenario, it is the relation of the CT V position to the whole body that has the highest effect on dose uncertainty.ConclusionOur method enables a more accurate analysis of the treatment plan robustness than the method currently implemented in EclipseTM TPS.