Medical physics international

Adaptive therapy involves the ability to alter a radiotherapy treatment plan based on tumor and anatomical changes over a course of therapy. The goal is to better target the tumor, reduce dose to healthy tissue and potentially improve overall outcomes. To date, achieving this has typically required time-consuming re-planning between treatment sessions or monopolizing a linac for an extended period while a patient waits on the treatment couch for new plans to be generated. Neither of these alternatives has been deemed practical or affordable at scale, as very often clinics don’t have the resources even if they have the tools. Consequently, Varian Medical Systems developed EthosTM therapy, a radiotherapy treatment system that uses artificial intelligence (AI) and machine learning to accomplish adaptive radiotherapy. In this paper, we describe the technology that underlies the adaptive capabilities of the system. Keywords— Adaptive radiotherapy, artificial intelligence, machine learning, Ethos, RapidPlan, treatment planning, neural networks, .