Evaluation of MVCT protocols for brain and head and neck tumor patients treated with helical tomotherapy
Evaluation of MVCT protocols for brain and head and neck tumor patients treated with helical tomotherapy
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DOI：
10.1016/j.radonc.2009.05.009
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发表时间：
2009-10-01
影响因子：
5.7
通讯作者：
Gregoire, Vincent
中科院分区：
文献类型：
--
作者：
Vaandering, Aude;Lee, John Aldo;Gregoire, Vincent
目的：螺旋断层放射治疗是一种放射治疗方式，它配备了一个机载成像设备，允许患者每天在内侧-外侧(m-L)、头尾(c-c)、前后(a-p)和横角度(滚)方向进行设置验证和校正。材料与方法：对75例5点固定热塑性口罩固定的头颈部癌症患者和30例3点固定热塑性口罩固定的脑肿瘤患者，将MVCT图像与治疗计划CT图像进行匹配，检测每天的设置误差。这个联合配准程序由系统软件自动完成(自动偏差)，然后由放射治疗师手动校正(总偏差)。系统误差和随机误差在患者和人群的基础上进行了分析。此外，对2种MVCT方案进行了回顾性评估；MVCT要么是在前五个分数(Fff)内获得的，要么是在隔周(Alt)获得的。根据先前的“MVCT”分数计算系统偏差，并在“非MVCT”分数期间应用。结果：H&N癌患者的总系统偏差(和随机偏差)分别为1.7 mm(1.4 mm)、1.6 mm(1.5 mm)、1.5 mm(1.5 mm)和0.6度(0.6度)，脑癌患者的m-L、c-c、c-c轴分别为1.6 mm(0.9 mm)、1.7 mm(1.1 mm)、1.1 mm(0.8 mm)和0.9度(0.6度)。分别为A-P方向和滚动方向。T检验检测到自动偏差和总偏差之间的微小但在统计学上有显著差异。两种MVCT方案都产生了相似的残余偏差。然而，对于H&N癌症患者，ALT方案导致较小的残余偏差和CTV-PTV边际，特别是在a-p方向。结论：总的系统和随机偏差与先前发表的数据相当。自动偏差和完全偏差之间没有临床差异。两种MVCT方案相似。但。对于H&N癌症患者，ALT方案产生的残余偏差较小，因此是减少治疗前MVCT频率的正确方案。(C)2009爱思唯尔爱尔兰有限公司。保留所有权利。放射治疗与肿瘤学93(2009)50-56
Purpose: Helical tomotherapy is a modality of radiation treatment delivery which is equipped with an on-board imaging device (MVCT) allowing for daily patient set-up verification and correction in the medial-lateral (m-l), cranial-caudal (c-c), anterior-posterior (a-p) and transversal angular (roll) directions. In this study, we measured set-up deviations and evaluated different MVCT protocols for brain and head and neck (H&N) cancer patients.Materials and methods: The daily set-up errors of 75 H&N cancer patients immobilized with 5-point fixation thermoplastic masks and 30 brain cancer patients immobilized with 3-point fixation thermoplastic masks were detected by matching the MVCT with the treatment planning CT images. This co-registration procedure was accomplished automatically by the system's software (automatic deviations), then corrected manually by the radiation therapists (total deviations). Systematic and random errors were analyzed on a patient and a population basis. Moreover, 2 MVCT protocols were retrospectively evaluated; MVCTs were either acquired during the first five fractions (FFFs) or on alternate week (ALT). Systematic deviations were calculated based upon prior "MVCT" fractions and applied during the "non-MVCT" fractions. The resulting residual deviations were then analyzed.Results: The total systematic (and random) deviations reached 1.7 mm (1.4 mm), 1.6 mm (1.5 mm), 1.5 mm (1.5 mm) and 0.6 degrees (0.6 degrees) for H&N cancer patients and reached 1.6 mm (0.9 mm), 1.7 mm (1.1 mm), 1.1 mm (0.8 mm) and 0.9 degrees (0.6 degrees) for brain cancer patients in the m-l, c-c, a-p and roll directions, respectively. A t-test detected small but statistically significant differences between the automatic and total deviations. Both MVCT protocols gave rise to similar residual deviations. However, for H&N cancer patients the ALT protocol resulted in smaller residual deviations and CTV-PTV margins, particularly in the a-p direction.Conclusion: The total systematic and random deviations were comparable to the previously published data. No clinical difference exists between the automatic and total deviations. Both MVCT protocols were similar. But. for H&N cancer patients, the ALT protocol gave rise to smaller residual deviations and therefore is the correct formula to adopt in order to reduce the frequency of pre-treatment MVCTs. (C) 2009 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 93 (2009) 50-56