3D打印模板辅助CT引导^(192)Ir组织间插植治疗复发妇科肿瘤的可行性分析

Feasibility of 3D-printing template-assisted and CT-guided ^(192)Ir interstitial brachytherapy in the treatment of recurrent gynecologic tumors

目的通过比较3D打印个体化模板(3D-PIT)辅助CT引导后装组织间插植治疗中央型复发妇科肿瘤的术前计划与术中实际物理剂量学参数,评价3D打印个体化模板辅助下CT引导的组织间插植治疗的剂量准确性。方法纳入分析2018年1月至2019年12月北京大学第三医院肿瘤放疗科中央型复发妇科肿瘤患者38例,均行3D打印个体化模板辅助CT引导^(192)Ir后装组织间插植治疗。大体肿瘤靶区(GTV)处方剂量10~36 Gy,2~6分次,5~6 Gy/次。比较患者治疗前、治疗时计划的90%靶区体积剂量(D_(90))、100%靶区体积剂量(D_(100))和100%处方剂量体积百分比(V_(100))。危及器官膀胱、直肠和结肠2 cm^3体积接受的剂量(D_(2 cm^3))。近距离治疗质量参数包括适形指数(CI)、均匀性指数(HI)、靶区外体积指数(EI)。同时观察围手术期并发症。结果研究共纳入治疗194例次,单次中位插植针6(5~13)根,单次处方剂量5~6 Gy。术前和术中的GTV D90、D100、V100、CI、HI、EI差异均无统计学意义(P>0.05)。术前和术中危及器官膀胱和结肠D2 cm3差异无统计学意义(P>0.05),术中直肠D_(2 cm^3)剂量略高于术前计划,差异有统计学意义(t=-0.335,P=0.027)。结论3D打印模板辅助CT引导下高剂量率^(192)Ir后装组织间插植治疗计划完成质量良好,达到术前剂量设计要求。

Objective To investigate the accuracy and feasibility of 3D-printing individualized template-guided and CT-guided ^(192)Ir interstitial brachytherapy in the central recurrent gynecologic tumors by comparing pre-plan and intraoperative physical dosimetric parameters.Methods This study involved 38 patients with central recurrent gynecologic tumors who underwent 3D printing individual template(3D-PIT)-assisted and CT-guided ^(192)Ir interstitial brachytherapy in the Department of Radiation Oncology of the Peking University Third Hospital from Jan 2018 to Dec 2019.The prescription doses for the target tumor areas were 10-36 Gy to be delivered at 5-6 Gy/fraction for 2-6 fractions.The pre-plan and intraoperative dosimetric parameters were compared,including the minimum prescription doses delivered to 90%and 100%of target volume(D_(90),D_(100))and the mean percentage of volume receiving 100%of the prescription doses(V_(100)).Meanwhile,the doses delivered to 2 cm^3(D_(2 cm^3))of organs at risk(bladders,rectums,and colons)were analyzed.The quality parameters of the brachytherapy were studied,including conformity index(CI),homogeneity index(HI),and external index(EI)of the target volume.Perioperative complications were also observed.Results A total of 194 treatments were included.During the treatment,5-13(median 6)needles were inserted,with a prescription dose of 5-6 Gy per fraction.There were no statistical differences between pre-plan and intraoperative _(D90),D_(100),V_(100),CI,HI,and EI as well as the D_(2 cm^3) of bladders and colons at risk(P>0.05).In contrast,for the D2 cm3 of rectums,the intraoperative dose was slightly higher than the pre-plan dose,showing a statistical difference(t=-0.335,P=0.027).Conclusions The 3D-PIT-assisted and CT-guided ^(192)Ir interstitial brachytherapy at a high dose rate is accurate and feasible in the treatment of recurrent gynecologic tumors,meeting the pre-plan dose requirement.