Algorithm for correcting optimization convergence errors in Eclipse

Abstract

Abstract: IMRT plans generated in Eclipse use a Dose Volume Optimizer (DVO) algorithm to evaluate dose for optimization and a more accurate algorithm for a final Volume Dose (VD) calculation, the Analytical Anisotropic Algorithm (AAA). The use of the DVO introduces Optimization Convergence Errors (OCE’s) into an IMRT plan. Eclipse has a feature where optimization may be performed on top of an existing base plan. When the base plan is an optimized IMRT plan, a second optimization can compensate for errors in the base plan. Errors in the base plan are demonstrated to originate in the DVO. An IMRT plan containing the same field arrangement as the initial base plan may be generated by adding the initial plan optimal fluence to the dose correcting plan optimal fluence. A simple procedure to correct DVO OCE’s which may be implemented in the clinic using the Eclipse Treatment planning system (TPS) is presented along with an Excel spreadsheet available for download to add fluence maps together.