文章：

质子治疗中儿童脑肿瘤患者摆位不确定性的前瞻性研究

Setup Uncertainty of Pediatric Brain Tumor Patients Receiving Proton Therapy: A Prospective Study

原文发布日期：20 November 2023

DOI: 10.3390/cancers15225486

类型: Article

开放获取: 是

英文摘要：

This study quantifies setup uncertainty in brain tumor patients who received image-guided proton therapy. Patients analyzed include 165 children, adolescents, and young adults (median age at radiotherapy: 9 years (range: 10 months to 24 years); 80 anesthetized and 85 awake) enrolled in a single-institution prospective study from 2020 to 2023. Cone-beam computed tomography (CBCT) was performed daily to calculate and correct manual setup errors, once per course after setup correction to measure residual errors, and weekly after treatments to assess intrafractional motion. Orthogonal radiographs were acquired consecutively with CBCT for paired comparisons of 40 patients. Translational and rotational errors were converted from 6 degrees of freedom to a scalar by a statistical approach that considers the distance from the target to the isocenter. The 95th percentile of setup uncertainty was reduced by daily CBCT from 10 mm (manual positioning) to 1–1.5 mm (after correction) and increased to 2 mm by the end of fractional treatment. A larger variation existed between the roll corrections reported by radiographs vs. CBCT than for pitch and yaw, while there was no statistically significant difference in translational variation. A quantile mixed regression model showed that the 95th percentile of intrafractional motion was 0.40 mm lower for anesthetized patients (p=0.0016). Considering additional uncertainty in radiation-imaging isocentricity, the commonly used total plan robustness of 3 mm against positional uncertainty would be appropriate for our study cohort.

摘要翻译： 

本研究量化了接受图像引导质子治疗的脑肿瘤患者的摆位不确定性。研究对象包括2020年至2023年间参与单中心前瞻性研究的165例儿童、青少年及年轻成人患者（放疗中位年龄：9岁（范围：10个月至24岁）；其中80例接受麻醉，85例保持清醒）。每日通过锥形束计算机断层扫描（CBCT）计算并校正手动摆位误差，每疗程摆位校正后测量一次残留误差，每周治疗后评估分次内运动。对40例患者连续采集正交X线片与CBCT进行配对比较。通过考虑靶区到等中心距离的统计方法，将平移和旋转误差从6自由度转换为标量值。每日CBCT使摆位不确定性的第95百分位数从10毫米（手动摆位）降低至1-1.5毫米（校正后），并在分次治疗结束时增加至2毫米。X线片与CBCT报告的翻滚校正差异较俯仰和偏航更大，而平移误差无统计学显著差异。分位数混合回归模型显示，麻醉患者分次内运动的第95百分位数降低0.40毫米（p=0.0016）。综合考虑放射-成像等中心性的额外不确定性，本研究中常用的3毫米计划鲁棒性阈值适用于当前研究队列。

原文链接：

Setup Uncertainty of Pediatric Brain Tumor Patients Receiving Proton Therapy: A Prospective Study