A technique for adaptive image-guided helical tomotherapy for lung cancer
A technique for adaptive image-guided helical tomotherapy for lung cancer
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DOI：
10.1016/j.ijrobp.2005.11.012
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发表时间：
2006-03-15
影响因子：
7
通讯作者：
Seibert, RM
中科院分区：
文献类型：
--
作者：
Ramsey, CR;Langen, KM;Seibert, RM
目的：许多肺癌患者在接受14次放射治疗后，其肿瘤体积（GTV）会逐渐缩小。随着肿瘤在治疗期间尺寸减小，GTV周围增加的边缘有效地变得更大，这可能导致正常肺组织的过度照射。本研究的具体目标是评估使用图像引导的自适应放射治疗的可行性，以调整规划目标体积每周基于前一周的CT图像集，用于图像引导patient setup.Methods和材料：兆伏计算机断层扫描（MVCT）图像的GTV上获得的螺旋断层治疗系统每天。这些图像用于定位患者并测量GTV体积的减少。进行了一项计划研究，以确定如果使用适应性治疗，可能达到的肺保护量。治疗计划的创建，其中目标体积减少后，肿瘤减少measured.Results：共158 MVCT成像会话进行了7例肺部患者。在治疗过程中，GTV降低了60-80%。治疗前60天的肿瘤缩小可以使用二阶多项式R=0.0002t（2）-0.0219t+1.0建模，其中R是GTV的缩小百分比，t是经过的天数。基于这些治疗计划研究，通过调整治疗输送，接受20戈伊的同侧肺的绝对体积可减少17%至23%（平均21%）。适应性治疗的好处是最大的肿瘤体积>= 25 cm（3），并直接依赖于GTV减少在treatment.Conclusions：兆伏CT为基础的图像引导可以用来定位肺癌患者的日常。这有可能减少与日常设置错误相关的利润。此外，本文中描述的适应性治疗技术可以减少接受20戈伊以上的健康肺组织的体积。然而，还需要进一步的研究来确定适应性治疗是否会导致微观延伸的剂量不足。(C)2006爱思唯尔公司
Purpose: The gross tumor volume (GTV) for many lung cancer patients can decrease during the course of 14 radiation therapy. As the tumor reduces in size during treatment, the margin added around the GTV effectively becomes larger, which can result in the excessive irradiation of normal lung tissue. The specific goal of this study is to evaluate the feasibility of using image-guided adaptive radiation therapy to adjust the planning target volume weekly based on the previous week's CT image sets that were used for image-guided patient setup.Methods and Materials: Megavoltage computed tomography (MVCT) images of the GTV were acquired daily on a helical tomotherapy system. These images were used to position the patient and to measure reduction in GTV volume. A planning study was conducted to determine the amount of lung-sparing that could have been achieved if adaptive therapy had been used. Treatment plans were created in which the target volumes were reduced after tumor reduction was measured.Results: A total of 158 MVCT imaging sessions were performed on 7 lung patients. The GTV was reduced by 60-80% during the course of treatment. The tumor reduction in the first 60 days of treatment can be modeled using the second-order polynomial R=0.0002t(2)-0.0219t+1.0, where R is the percent reduction in GTV, and t is the number of elapsed days. Based on these treatment planning studies, the absolute volume of ipsilateral lung receiving 20 Gy can be reduced between 17% and 23% (21% mean) by adapting the treatment delivery. The benefits of adaptive therapy are the greatest for tumor volumes >= 25 cm(3) and are directly dependent on GTV reduction during treatment.Conclusions: Megavoltage CT-based image guidance can be used to position lung cancer patients daily. This has the potential to decrease margins associated with daily setup error. Furthermore, the adaptive therapy technique described in this article can decrease the volume of healthy lung tissue receiving above 20 Gy. However, further study is needed to determine whether adaptive therapy could result in the underdosing of microscopic extension. (C) 2006 Elsevier Inc.