Intra-fraction motion of the prostate during treatment with helical tomotherapy
Intra-fraction motion of the prostate during treatment with helical tomotherapy
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DOI：
10.1016/j.radonc.2013.09.011
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发表时间：
2013-12-01
影响因子：
5.7
通讯作者：
Burnet, Neil G.
中科院分区：
文献类型：
--
作者：
Thomas, Simon J.;Ashburner, Mark;Burnet, Neil G.
背景与目的：测量图像引导前列腺放疗患者在TomoTherapy上的分数内运动和观察者内图像匹配所产生的几何不确定性。材料和方法：所有患者均已选择前列腺放射治疗TomoTherapy，每日MV-CT成像。这项研究包括在37次治疗过程中，在治疗结束时进行5次额外的MV-CT成像。研究招募了54名患者。导出了计算分数内运动PTV余量的新公式。结果：LR、SI、AP和roll的分数内差均值分别为0.0 mm、0.5 mm、0.5 mm和0.0度。系统不确定度标准差分别为1.1 mm、0.8 mm、0.8 mm和0.6度，随机不确定度标准差分别为1.3 mm、2.0 mm、2.2 mm和0.3度。这种分数内运动需要在LR方向2.2 mm， SI方向2.1 mm和AP方向2.1 mm的边缘。考虑到旋转和匹配误差的影响，这些边际在LR方向增加到约4毫米，在SI和AP方向增加到5毫米。结论：开发了一种新的边缘配方来计算分数内运动的边缘。本配方适用于任何基于处理前后图像差异的测量技术。2013爱思唯尔爱尔兰有限公司版权所有。
Background and purpose: To measure the geometric uncertainty resulting from intra-fraction motion and intra-observer image matching, for patients having image-guided prostate radiotherapy on TomoTherapy.Material and methods: All patients had already been selected for prostate radiotherapy on TomoTherapy, with daily MV-CT imaging. The study involved performing an additional MV-CT image at the end of treatment, on 5 occasions during the course of 37 treatments.. 54 patients were recruited to the study. A new formula was derived to calculate the PTV margin for intra-fraction motion.Results: The mean values of the intra-fraction differences were 0.0 mm, 0.5 mm, 0.5 mm and 0.0 degrees for LR, SI, AP and roll, respectively. The corresponding standard deviations were 1.1 mm, 0.8 mm, 0.8 mm and 0.6 degrees for systematic uncertainties (Sigma), 1.3 mm, 2.0 mm, 2.2 mm and 0.3 degrees for random uncertainties (sigma). This intra-fraction motion requires margins of 2.2 mm in LR, 2.1 mm in SI and 2.1 mm in AP directions. Inclusion of estimates of the effect of rotations and matching errors increases these margins to approximately 4 mm in LR and 5 mm in SI and AP directions.Conclusions: A new margin recipe has been developed to calculate margins for intra-fraction motion. This recipe is applicable to any measurement technique that is based on the difference between images taken before and after treatment. (C) 2013 Elsevier Ireland Ltd. All rights reserved.