宫颈癌后装放疗中剂量的体积优化和逆向模拟退火优化的比较分析

Dosimetric comparison of volume- versus inverse planning simulated annealing-based dose optimizations in afterloading brachytherapy for cervical cancer

目的:比较宫颈癌腔内联合组织间插植三维后装计划中体积优化和模拟退火逆向优化(IPSA)剂量分布的差异,为其在治疗中计划设计优化方案的选择提供依据。方法:选取15例进行了三维后装治疗的宫颈癌患者,原执行体积优化,基于原始图像重新设计IPSA计划,配对t检验两种优化方法的剂量学差异。结果:在两组间靶区V_(100%)和V_(150%)以及均匀性指数方面无统计学差异(P>0.05)。而靶区的适形度指数的平均值有着显著差异[体积优化(0.77±0.11),IPSA优化(0.82±0.07)],且具有统计学差异(P<0.05)。在OAR方面,与体积优化相比,IPSA优化使OAR的受照剂量明显降低,统计学差异明显(P<0.05)。结论:与体积优化方法相比,IPSA优化在提高靶区适形度指数的同时,更好地对OAR起到保护作用,且计算过程相对简捷,是临床上更可取的计划优化算法。

Objective To compare the differences of dose distributions between volume-and inverse planning simulated annealing(IPSA)-based optimizations in three-dimensional(3D)afterloading brachytherapy plan of cervical carcinoma,and provide the reference for the selection of the plan optimization in 3D afterloading brachytherapy of cervical cancer.Methods Fifteen cases of cervical cancer treated with 3D afterloading brachytherapy were enrolled in this study,and the original optimization was based on volume.Herein another optimization plans based on IPSA were designed based on the original images.Paired t test was used to analyze the dosimetric differences between two optimization methods.Results The V100%,V150%and homogeneity index of target areas were similar in two groups,without statistical differences(P>0.05).The average value of target conformity index in IPSA-based optimization plans was higher than that in volume-based optimization plans,with statistical differences(0.82+0.07 vs 0.77+0.11,P<0.05).Compared with volume-based optimization,IPSA-based optimization significantly reduced the organs-at-risk dose,and the difference was statistically significant(P<0.05).Conclusion IPSA-based optimization is superior to volume-based optimization in target conformity index,organs-at-risk sparing,and the calculation process of IPSA-based optimization is relatively simple,which make IPSA-based optimization be a preferable choice in clinic.