作　　者： (晏俊芳）; (于浪）; (胡克）; (侯晓荣）; (沈捷）; (连欣）; (刘志凯）; (张福泉）;

机构地区： 中国医学科学院北京协和医学院北京协和医院放射治疗科,北京100730

出　　处： 《中华放射肿瘤学杂志》 2017年第9期1045-1049,共5页

摘　　要： 目的 分析三维正、逆向、二维计划模式下宫颈癌腔内放疗分次间剂量变化,探讨短间隔内非同次施源器置入术隔次计划实施的风险。方法 回顾比较我科收治的11例根治性放疗宫颈癌患者的25组间隔≤4 d的连续2次CT引导下腔内放疗计划。将同一组内前次腔内放疗计划（Plan-1）的驻留位置和时间模拟至后次腔内放疗CT图像上形成Plan-1-S,记录3种计划模式下的靶区覆盖指标及OAR的D 2 cc,并与后次实际计划（Plan-2）比较。采用配对t检验、Wilcoxon符号秩检验及方差分析。结果 逆向模式Plan-1-S的高危CTV的D90、D100、V100较实际计划分别下降（-9.11±13.46）%、（-13.16±18.79）%、（-7.80±13.34）%（P=0.002、0.002、0.005）。逆向模式隔次计划D90、D100、V100下降比例最高,分别为76%、80%、76%,D90、D100、V100最大下降值分别332.14 cGy （二维）、244.12 cGy （正向）、41.76%（逆向）。正向模式下OAR超量比例最高,D90、D100、V100下降伴1个OAR超量分别占29.41%、37.50%、25.00%,伴2个OAR超量分别占5.88%、12.50%、6.25%。小肠是超量最多器官,发生率达36%。3种模式比较中,逆向计划各靶区覆盖指标下降程度较二维计划最大。结论 无论哪种计划模式,即使短间隔,隔次模拟计划均有明显降低靶区覆盖、增加OAR超量发生的高风险,不建议临床应用。 Objective To examine the interfractional dosimetric variations among inverse three-dimensional （3D） plan, forward 3D plan, and two-dimensional （2D） plan of intracavitary brachytherapy for cervical cancer, and to discuss the risk of implementing the interval plan on different implantation applicators at short time intervals. Methods Twenty-five groups of CT-guided intracavitary brachytherapy （two consecutive radiations at ≤4 d apart） plans from 11 cervical cancer patients who received radical radiation therapy in our hospital were reviewed and compared. The dwelling location and time of the first intracavitary brachytherapy plan （Plan-1） were simulated on the CT image of the second intracavitary brachytherapy to form Plan-1-S. The target coverage indices and D 2 cc of organs at risk （OARs） of Plan-1-S and Plan 2（actual plan of the second intracavitary brachytherapy） under the three planning modes were recorded and compared using the paired t-test, Wilcoxon signed rank test, and ANOVA. Results The D90, D100, and V100 of high-risk CTV were significantly lower in Plan-1-S created under the inverse mode in the actual plan （-9.11±13.46%,-13.16±18.79%, and -7.80±13.34%, P=0.002, 0.002, and 0.005, respectively）. D90, D100, and V100 of the interval plan had the greatest reduction under the inverse mode （76%, 80%, and 76%, respectively）. The maximum reductions in D90, D100, and V100 were 332.14 cGy （2D）, 244.12 cGy （forward）, and 41.76%（inverse）. OAR overdose occurred most frequently under the forward mode;the rates of D90, D100, and V100 reductions accompanied by one OAR overdose were 29.41%, 37.50%, and 25.00%, and the rates of D90, D100, and V100 reductions by two OAR overdoses were 5.88%, 12.50%, and 6.25%,respectively. Overdose occurred most frequently in the small intestine （36%）. Comparison of the three planning modes showed that the inverse plan had a greater reduction in each target coverage index than the 2D plan. Conclusions The simulated interval plan can sig

关 键 词： 宫颈肿瘤 近距离治疗 分次间剂量 隔次计划