title: General strategy for the protection of organs at risk in IMRT therapy of a moving body.
abstract: We investigated protection strategies of organs at risk (OARs) in intensity modulated radiation therapy (IMRT). These strategies apply to delivery of IMRT to moving body anatomies that show relative displacement of OAR in close proximity to a tumor target. We formulated an efficient genetic algorithm which makes it possible to search for global minima in a complex landscape of multiple irradiation strategies delivering a given, predetermined intensity map to a target. The optimal strategy was investigated with respect to minimizing the dose delivered to the OAR. The optimization procedure developed relies on variability of all parameters available for control of radiation delivery in modern linear accelerators, including adaptation of leaf trajectories and simultaneous modification of beam dose rate during irradiation. We showed that the optimization algorithms lead to a significant reduction in the dose delivered to OAR in cases where organs at risk move relative to a treatment target.
authors: Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors: Ramin M
authors: RM
authors: Abolfath
authors: Lech
authors: L
authors: Papiez
mesh_terms: D000465:Algorithms; D006801:Humans; D009068:Movement; D010315:Particle Accelerators; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012306:Risk; D013997:Time Factors