Clinical implications of Acuros planning in lung, head and neck and prostate treatments

Abstract

The introduction of a highly accurate algorithm, Acuros XB (AXB), in the Eclipse^TM treatment planning system, implies changes in calculated patient dose distributions compared to the previous one, Anisotropic Analytical Algorithm (AAA), mainly in areas with very different density from water.

The purpose of this work is to ensure a safe transition from AAA to AXB, investigating the dosimetric  differences that can be derived from the use of AXB, in representative points of the dose volume histogram  (DVH), both for the planning target volume (PTV), and for the organs at risk involved (OAR) traditionally established, and proposing, when required, additional statistically calculated restrictions for the traditionally established OAR tolerance criteria.

Representative samples of patients are selected for 3 different locations (17 lung, 15 prostate and 15 head and neck patients), planned with AAA and treated with VMAT technique; and then recalculated with AXB, without optimizing again. The differences found in the relevant parameters of the HDV are evaluated, focusing on those points where these are statistically significant and affect an OAR, which could have negative clinical implications. In these cases the restriction above mentioned is proposed.

For PTV, the planning of treatments with AXB would improve the coverage of target volumes, especially in lung and head and neck locations.