乌德勒支施源器用于局部晚期宫颈癌三维近距离放疗的剂量学研究

Dosimetric impacts of Utrecht applicator on three-dimensional brachytherapy for advanced cervical carcinoma

目的探讨在使用乌德勒支施源器治疗局部晚期宫颈癌时,不同的管道组合设计与靶区、危及器官(OAR)的剂量关系。方法调取2017—2018年于河北省沧州中西医结合医院放疗科接受乌德勒支施源器进行近距离治疗的17例局部晚期宫颈癌患者数据,原计划为腔内联合组织间插植近距离放疗(IC/IS),在原勾画轮廓与照射剂量不变的情况下,去除插植针完成腔内近距离放疗(IC)计划设计,对IC/IS计划和IC计划的剂量参数进行对比分析,并评价加入IS插植针对剂量的影响。结果IC/IS和IC计划的高危临床靶区(HR-CTV)总的D90分别(88.68±1.84)和(85.54±0.54)Gy,差异具有统计学意义(t=6.200,P<0.05)。此外,在靶区的CI指数上,IC/IS计划的明显高于IC计划(0.58±0.08,0.43±0.05),差异具有统计学意义(t=1.010,P<0.05)。在两种计划中危及器官(OAR)的受照剂量差异无统计学意义(P>0.05)。结论对于局部晚期宫颈癌的近距离治疗,使用乌德勒支施源器可满足其处方剂量覆盖,而加入IS针,提高了计划的优化空间,在满足OAR受照剂量限值的基础上,显著提高HR-CTV的受照剂量,且提升了剂量分布均匀性。

Objective To investigate the effect of Utrecht applicator on dosimetrics of targets and OARs in brachytherapy for advanced cervical cancer.Methods Data of patients with locally advanced cervical cancer who received brachytherapy with Utrecht Source Applicator from 2017 to 2018 in the Department of Radiotherapy,Cangzhou Hospital of Integrated Traditional Chinese and Western Medicine,Hebei province,were collected.The original plan was intracavitary/interstitial brachytherapy(IC/IS-BT).With the original contour and prescription dose unchanged,the implantation was removed and new intracavitary brachytherapy(IC)plan was designed.The dosimetric parameters of IC/IS plan and IC plan were compared and analyzed,and the effect of IS implantation on dose was evaluated.Results The D90 of HR-CTV was(88.68±1.84)Gy in IC/IS group and(85.54±0.54)Gy in IC group,with significant difference(t=6.200,P<0.05).In addition,conformity index of the IC/IS plan was significantly higher than that of the IC plan(IC/IS:0.58±0.08,IC:0.43±0.05;t=1.010,P<0.05).In terms of OAR,there was no significant difference in dosage between the two groups(P>0.05).Conclusions For the brachytherapy of locally advanced cervical cancer,the use of Utrecht Source Applicator can satisfy the prescription dose coverage.Adding IS insertion needle can improve the optimization space of the plan.Without exceeding the dose limit of OAR,the radiation dose to HR-CTV can be significantly increased,and the uniformity of dose distribution can be improved as well.