ESTRO 2021 Abstract Book

S212

ESTRO 2021

Results With a similar planning objective value, number of energy layers and spots, both SPArc DMSP speed plans could be delivered continuously within the ±1 degree tolerance window. It was exciting to find out that the SPArc DMSP-user-speed plan could minimize the gantry momentum change during the proton arc treatment delivery based on clinical users' input. This new algorithm could not only meet the clinical user's needs in terms of the plan quality and treatment delivery efficiency but also help relieve mechanical challenges to accelerate or decelerate the hundreds of tons of gantry which could be critical to different proton systems' hardware and software requirements (Figure 2). and SPArc DMSP-user-

Conclusion