目的:Ethos(瓦里安医疗系统)放射治疗设备结合了半自动解剖检测和计划生成,用于基于锥形束计算机断层扫描(CBCT)的每日在线自适应放射治疗(oART)。然而,CBCT提供比磁共振成像(MRI)更少的软组织对比度。这项工作旨在介绍基于CBCT的oART与基于穿梭的离线MR指导的临床工作流程。
方法:从2023年2月至11月,31例患者接受了Ethos放疗(Varian,帕洛阿尔托,CA,美国)支持机器学习(ML)的系统-每日oART。此外,患者每周在治疗位置接受MRI检查,用于日常计划调整,通过基于航天飞机的系统。使用Ethos治疗计划系统生成初始和调整后的治疗计划。患者临床数据,分数会话时间(MRI+穿梭运输+定位,适应,QA,对所有患者的所有分数进行RT交付)和计划选择评估。
结果:总计,应用了737个oART级分,并获得了118个MRI用于离线MR指导。肿瘤的主要部位是前列腺(n=16),肺(n=7),子宫颈(n=5),膀胱(n=1)和子宫内膜(n=2)。所有患者均完成治疗。包括穿梭运输和定位到Ethos自适应会话开始的中位MRI采集时间为53.6分钟(IQR46.5-63.4)。无MRI的中位总治疗时间为30.7分钟(IQR24.7-39.2)。分别,中位数适应,计划QA和RT时间为24.3分钟(IQR18.6-32.2),0.4分钟(IQR0.3-1,0)和5.3分钟(IQR4.5-6.7),分别。在97.7%的病例中,选择了适应计划而不是计划计划。
结论:本研究描述了迄今为止基于CBCT的oART与基于穿梭的离线MR指导方法相结合的第一个工作流程。报告的oART持续时间类似于先前出版物对Ethos系统的首次临床经验所显示的范围。
The
Ethos (Varian Medical Systems) radiotherapy device combines semi-automated anatomy detection and plan generation for cone beam computer tomography (CBCT)-based daily online adaptive radiotherapy (oART). However, CBCT offers less soft tissue contrast than magnetic resonance imaging (MRI). This work aims to present the clinical workflow of CBCT-based oART with shuttle-based offline MR guidance.
From February to November 2023, 31 patients underwent radiotherapy on the
Ethos (Varian, Palo Alto, CA, USA) system with machine learning (ML)-supported daily oART. Moreover, patients received weekly MRI in treatment position, which was utilized for daily plan adaptation, via a shuttle-based system. Initial and adapted treatment plans were generated using the
Ethos treatment planning system. Patient clinical data, fractional session times (MRI + shuttle transport + positioning, adaptation, QA, RT delivery) and plan selection were assessed for all fractions in all patients.
In total, 737 oART fractions were applied and 118 MRIs for offline MR guidance were acquired. Primary sites of tumors were prostate (n = 16), lung (n = 7), cervix (n = 5), bladder (n = 1) and endometrium (n = 2). The treatment was completed in all patients. The median MRI acquisition time including shuttle transport and positioning to initiation of the
Ethos adaptive session was 53.6 min (IQR 46.5-63.4). The median total treatment time without MRI was 30.7 min (IQR 24.7-39.2). Separately, median adaptation, plan QA and RT times were 24.3 min (IQR 18.6-32.2), 0.4 min (IQR 0.3-1,0) and 5.3 min (IQR 4.5-6.7), respectively. The adapted plan was chosen over the scheduled plan in 97.7% of cases.
This study describes the first workflow to date of a CBCT-based oART combined with a shuttle-based offline approach for MR guidance. The oART duration times reported resemble the range shown by previous publications for first clinical experiences with the
Ethos system.