驻留时间差异限制对宫颈癌三维后装放疗计划的影响  

Effect of dwell time deviation constraint on the three-dimensional brachytherapy plans for cervical cancer

作　　者：曹瑛 杨振[1] 唐杜 杨晓喻[1] Cao Ying;Yang Zhen;Tang Du;Yang Xiaoyu(Department of Oncology,National Clinical Research Center for Geriatric Disorders,Xiangya Hospital Central South University,Changsha 410008,China)

机构地区：[1]中南大学湘雅医院肿瘤科,中南大学湘雅医院国家老年疾病临床医学研究中心,长沙410008

出　　处：《中华放射肿瘤学杂志》2023年第8期711-717,共7页Chinese Journal of Radiation Oncology

基　　金：国家自然科学基金(12005306);湖南省自然科学基金(2021JJ40960,2021JJ40966,2022JJ30976)。

摘　　要：目的研究逆向优化过程中驻留时间差异限制参数对宫颈癌三维后装计划质量和位置误差鲁棒性的影响。方法回顾性选择2020年8月至2021年8月于中南大学湘雅医院接受宫颈癌三维后装治疗的20例患者。使用Eclipse计划系统进行计划设计,分别将计划系统中的驻留时间差异限制参数smooth值设置为0.00、0.25、0.50、0.75、1.00,采用逆向剂量体积优化算法生成不同的smooth计划,优化条件同原始临床计划,对比分析关键剂量学指标和总驻留时间差异。对施源器人为引入左右、腹背和头脚六个方向的位置误差(0.2~1.0cm),评估不同smooth值对计划质量和鲁棒性的影响。每个病例133个计划,20例患者共计2660个计划。采用Wilcoxon符号秩检验对结果进行统计分析。结果随着smooth值增大,调制因子逐渐减小,膀胱和直肠D_(2cm^(3))增大。smooth值为0.25、0.50、0.75、1.00计划的调制因子分别为0.72±0.09、0.63±0.08、0.55±0.08、0.51±0.06,均低于sm0oth值为0.00计划的调制因子0.75±0.05,差异均有统计学意义(P=0.004、0.002、0.002、0.002);smooth值为0.50、0.75、1.00计划的膀胱D_(2cm^(3))分别为(475.4±41.0)、(483.7±46.2)、(489.0±46.8)cGy,均高于smooth值为0.00计划的膀胱D_(2cm^(3)),值为(469.8±41.8)cGy,差异有统计学意义(P均=0.002);smooth值为0.50、0.75计划的直肠D_(2cm^(3))分别为(413.2±93.3)、(418.6±96.4)cGy,均高于smooth值为0.00计划的直肠D_(2cm^(3)),值为(410.2±91.5)cGy,差异有统计学意义(P=0.006、0.010)。当引入位置误差后,多数位置误差下不同smooth计划的高危临床靶区(HR-CTV)D_(90%)接近,差异无统计学意义;smooth值为0.00计划的危及器官D_(2cm^(3))均低于其他smooth值计划,对于膀胱和直肠,此差异在多数位置误差下都有统计学意义(P<0.01)。结论驻留时间差异限制参数对计划质量影响较大,限制参数越小,计划质量越高;驻留时间差异限制参数对靶区和关键危及器Objective To investigate the effect of dwell time deviation constraint of inverse optimization on the quality and position error robustness of three-dimensional(3D)brachytherapy plans for cervical cancer.Methods A total of 20 patients with cervical cancer receiving 3D brachytherapy treatment in Xiangya Hospital Central South University from August 2020 to August 2021 were retrospectively selected.All plans were designed using the Eclipse treatment planning system,and the dwell time deviation constraint parameter smooth value in the system were set to 0.00,0.25,0.50,0.75,and 1.00,respectively.An inverse dose volume optimization algorithm was used to generate plans with various smooth values,and the optimization conditions were the same as the original clinical plans.Key dosimetric metrics and total dwell time differences were comparatively analyzed.The applicators were intentionally subjected to position errors(0.2-1.0 cm)in 6 directions(left-right,anterior-posterior,head-foot),and the effect of various smooth values on plan quality and robustness was assessed.There were 133 plans per case and 2660 plans for 20 patients.The results were statistically analyzed using the Wilcoxon signed-rank nonparametric test.Results As the smooth value was increased,the modulation factor was gradually decreased and the Dzem3 of the bladder and rectum was increased.Plans with smooth values of 0.25,0.50,0.75,1.00 had modulation factors of 0.72±0.09,0.63±0.08,0.55±0.08,0.51±0.06,respectively,lower than 0.75±0.05 of the plan with the smooth value of 0.00,and all differences were statistically significant(P=0.004,0.002,0.002,0.002).The bladder D_(2cm^(3))of plans with smooth values of 0.50,0.75,1.00 were(475.4±41.0)cGy,(483.7±46.2)cGy,and(489.0±46.8)cGy,respectively,higher than(469.8±41.8)cGy of the plan with the smooth value of 0.00,with statistically significant differences(all P=0.002).The rectum D2 em3 of plans with smooth values of 0.50 and 0.75 plans were(413.2±93.3)cGy and(418.6±96.4)cGy,both higher than(410.2±91.5)c

关 键 词：宫颈肿瘤 三维后装放射疗法 计划优化 驻留时间差异限制 

分 类 号：R737.33[医药卫生—肿瘤]