AbstractID: 9546 Title: Deformable dose registration and treatment planning approaches
Patient imaging during or after radiotherapy treatment offers various possibilities and challenges not available before about how to
deal with the overall treatment planning and delivery process. Treatment planning and actual delivery depends on issues such as the
capabilities for patient setup (rigid body, accounting for deformation), on-line planning corrections and/or optimization, reoptimization, etc.
The present work analyzes pros and cons of different planning strategies and techniques without and with anatomical deformations
accounted for. When anatomical changes are considered, a deformable dose registration approach is used. This kind of technique maps
back all the CTs to a common CT framework and the same map is used to map back all of the daily dose distributions. Prostate
patients with daily CT images have been retrospectively analyzed. Optimization schemas such as one single optimization for the full
treatment, adaptive and multi-margin optimization and daily on-line optimization have been analyzed. As it can be expected our
results support that the tumor is covered given large enough margins when deformable dose registration is used. However, regarding
the sensitive structures, when anatomy deformations are considered the planning strategy to be used may have clear impact on the
final outcome of the plan, and in some cases even daily online optimization may not offer better solutions than an off line modification
of the treatment plan.