Quality improvement process to assess tattoo alignment, set-up accuracy and isocentre reproducibility in pelvic radiotherapy patients
Quality improvement process to assess tattoo alignment, set-up accuracy and isocentre reproducibility in pelvic radiotherapy patients
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DOI：
10.1002/jmrs.79
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发表时间：
2014-12-01
影响因子：
2.1
通讯作者：
Roderick, Stephanie
中科院分区：
文献类型：
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作者：
Elsner, Kelly;Francis, Kate;Roderick, Stephanie
前言：这项质量改进研究测试了纹身对齐和等中心定义的三种方法，以调查对齐横向纹身以最大限度地减少俯仰、侧滚和偏航是否减少了设置误差，以及使用头尾位置的横向纹身来定义等中心是否提高了等中心重复性。研究人群是接受前列腺癌根治性外放射治疗(EBRT)的患者。研究结果适用于所有仰卧位盆腔EBRT患者。方法：3个序贯队列分别纳入11例、11例和10例患者。为每个患者采集了由20对正交门静脉图像(EPI)组成的数据集。EPI与数字化重建的X光照片进行了离线匹配。在队列1中，横向纹身进行了调整，以最大限度地减少侧滚。前部纹身用来定义等中心点。在队列2中，横向纹身被排成一列，以最大限度地减少侧滚和偏航。根据队列1定义等中心。在队列3中，横向纹身按照队列2排列，而前部纹身被调整以最小化螺距。等中心纹身定义为CC位置的侧面纹身和左右位置的前部纹身。结果：从队列1到队列3，CC系统误差从-1.3 mm减少到-0.5 mm，随机设置误差从3.1 mm减少到1.4 mm，队列3的结果更好。治疗中心的重复性也从86.7%提高到92.1%。结论：在队列3中纹身对齐和等中心定义的方法减少了设置误差，提高了等中心重复性。
Introduction: This quality improvement study tested three methods of tattoo alignment and isocentre definition to investigate if aligning lateral tattoos to minimise pitch, roll and yaw decreased set-up error, and if defining the isocentre using the lateral tattoos for cranio-caudal (CC) position improved isocentre reproducibility. The study population was patients receiving curative external beam radiotherapy (EBRT) for prostate cancer. The results are applicable to all supine pelvic EBRT patients. Methods: The three sequential cohorts recruited 11, 11 and 10 patients respectively. A data set of 20 orthogonal pairs of electronic portal images (EPI) was acquired for each patient. EPIs were matched offline to digitally reconstructed radiographs. In cohort 1, lateral tattoos were adjusted to minimise roll. The anterior tattoo was used to define the isocentre. In cohort 2, lateral tattoos were aligned to minimise roll and yaw. Isocentre was defined as per cohort 1. In cohort 3, lateral tattoos were aligned as per cohort 2 and the anterior tattoo was adjusted to minimise pitch. Isocentre was defined by the lateral tattoos for CC position and the anterior tattoo for the left-right position. Results: Cohort 3 results were superior as CC systematic and random set-up errors reduced from -1.3 mm to -0.5 mm, and 3.1 mm to 1.4 mm respectively, from cohort 1 to cohort 3. Isocentre reproducibility also improved from 86.7% to 92.1% of treatment isocentres within 5 mm of the planned isocentre. Conclusion: The methods of tattoo alignment and isocentre definition in cohort 3 reduced setup errors and improved isocentre reproducibility.