ESTRO 2024 - Abstract Book

S4593

Physics - Optimisation, algorithms and applications for ion beam treatment planning

ESTR0 2024

compromises or unintended OAR dosage. This underlines the importance of a 3-dimensional dose correction before dose summation.

Keywords: Reirradiation, EQD2 dose summation, Rectum cancer

423

Digital Poster

Design a time-efficient proton arc treatment system controller

Xiaoda Cong 1 , Gang Liu 1,2 , Peilin Liu 1 , Lewei Zhao 1,3 , Shupeng Chen 1 , Rohan Deraniyagala 1 , Craig Stevens 1 , Xiaoqiang Li 1 , Xuanfeng Ding 1 1 William Beaumont University Hospital, Corewell Health, Department of Radiation Oncology, Royal Oak, USA. 2 Union Hospital, Department of Radiation Oncology, Wuhan, China. 3 Stanford University, Department of Radiation Oncology, Stanford, USA

Purpose/Objective:

Proton arc therapy enables the continuous delivery of proton beams while rotating the gantry. [1] One of the critical components in the proton arc system is the controller's design, which decides the irradiation sequence and gantry rotation speed [2]. This study aims to develop a novel system controller by optimizing the gantry rotation speed and control point connection in order to deliver the proton arc plans efficiently.

Material/Methods:

This time-efficient proton arc system controller (controller -time-efficient ) aims at optimizing the overall efficiency within tolerance windows, ensuring feasibility by adjusting the speed between tolerance windows. It first calculates the maximum average speed of each tolerance window. Then, the maximum speed to enter and exit the tolerance window can be decided by minimizing the speed while delivery and maintaining the same average speed within the tolerance window as the maximum average speed. After that, an optimal schedule between each window can be calculated by accelerating to the maximum speed allowed between adjacent windows and then decelerating to the entering speed of the next tolerance window. In case this cannot be achieved due to the gantry mechanical constraints, the algorithm will go backward to find a feasible point to decelerate in case the entering speed of the next tolerance window. Five different disease sites e.g., liver, head neck, intracranial, lung, and prostate cancer cases, were used for testing purposes. As a benchmark, the plans were also simulated with the first prototype proton arc system controller (controller -prototype ). Total dynamic delivery time, statice delivery time, lost time [Lost time = Dynamic delivery time – static delivery time], and gantry speed were compared between the controller -time-efficient and controller prototype.