Department of Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN 38120, USA.
Radiother Oncol. 2010 Dec;97(3):399-403. doi: 10.1016/j.radonc.2010.10.017. Epub 2010 Nov 11.
Investigate the effect of tumor change and setup uncertainties on target coverage for pediatric craniopharyngioma during RT.
Fifteen pediatric patients with craniopharyngioma (mean 5.1 years) were included in this study. MRI was performed before and a median of six times during RT to monitor changes in the tumor volume. IMRT plans were created and compared to the CRT plan used for treatment. The role of adaptive therapy based on GTV changes was investigated. Dosimetric effects of interfraction and intrafraction motion were examined.
The mean of the maximal change in the GTV was 28.5% [-20.7% to 82.0%]. For the standard margin IMRT plans, the mean D(95) of the base plan on the base target was 53.6 Gy [53.1-54.1]. The mean D(95) of the base plans on the adaptive targets was 52.1 Gy [47.9-54.1]. The D(95) for the adaptive plan on the adaptive target was 53.8 Gy [53.4-54.3]. A linear regression equation of y=-0.12x , r(2)=0.70, was found for the percent change in D(95) of the PTV (y) vs. the percent change in the GTV (x). Inter and intrafraction motion did not affect the target coverage for standard and reduced margin plans.
The GTV of pediatric craniopharyngioma patients change size during therapy and adaptive planning is critical for conformal plans; therefore early and regular surveillance imaging is required.
研究肿瘤变化和设置不确定性对儿童颅咽管瘤放射治疗期间靶区覆盖的影响。
本研究纳入了 15 例儿童颅咽管瘤患者（平均年龄 5.1 岁）。在放射治疗前和治疗期间中位数进行了 6 次 MRI 检查，以监测肿瘤体积的变化。创建了调强放疗计划，并与用于治疗的常规放疗计划进行了比较。研究了基于 GTV 变化的自适应治疗的作用。检查了分次间和分次内运动对剂量学的影响。
GTV 的最大变化平均值为 28.5%[-20.7%至 82.0%]。对于标准边界调强放疗计划，基础靶区基础计划的平均 D95 为 53.6Gy[53.1-54.1]。自适应靶区基础计划的平均 D95 为 52.1Gy[47.9-54.1]。自适应靶区自适应计划的 D95 为 53.8Gy[53.4-54.3]。发现 PTV（y）的 D95 变化百分比与 GTV（x）的变化百分比之间存在线性回归方程 y=-0.12x，r2=0.70。对于标准和减少边界计划，分次间和分次内运动不会影响靶区覆盖。
儿童颅咽管瘤患者的 GTV 在治疗过程中会发生变化，因此自适应计划对于保形计划至关重要；因此，需要早期和定期进行监测成像。
