CT引导辅助3D打印个体化非共面模板引导^125 I粒子治疗头颈部复发／转移肿瘤剂量学研究

Dosimetry verification of radioactive seed implantation for recurrent malignant tumor of head and neck assisted by 3D printing individual guide plate

目的对比3D打印模板辅助放射性粒子植人治疗头颈部复发／转移恶性肿瘤的术前计划与术后验证的剂量学结果，在剂量学层面探讨该技术的治疗精确性。方法回顾性分析2016年1月一2016年12月于北京大学第三医院接受3D打印模板辅助CT引导放射性125 I粒子植入的头颈部复发／转移恶性肿瘤的患者共42例。处方剂量给予110～160 Gy。所有患者行术前计划设计、3D打印模板制作、穿刺及粒子植入,术后验证的剂量学结果与术前计划相对比，剂量学参数包括D90、mPD、V100、V150、V200、适形指数（CI）、靶区外体积指数（EI）、均匀性指数（HI）。统计学方法采用配对t检验。结果设计并制作3D打印模板42块。入组患者的GTV平均体积为28．6cm^3，术后GTV平均D90 142．6 Gy。术后验证D90、mPD、V100、V150、V200的均值分别为142．6Gy、77．3Gy、92．48％、68．40％、42．98％，术前则分别为144．5和70．2Gy、91．45％、63．12％、34．74％。其中D90、V100、CI、EI、HI术前术后差异无统计学意义（P＞0．05）。mPD、V150、V200术前术后比较差异有统计学意义（t=-2．166、-2．863、-4．778，P〈0．05）。结论3D打印模板定位、定向准确，针对头颈部复发／转移恶性肿瘤，术后验证实际剂量分布主要指标均较好地达到了术前预计划的设计要求，有良好的治疗精确性。

Objective To compare the dose distributions of postoperative plans with preoperative plans for 3D printing guide plate assist radioactive seeds implantations, explore the effects of the technology for seeds implantations in dosimetry level. Methods From January 2016 to December 2016, a total of 42 patients of local recurrent malignant tumor of head and neck received 3D printing guide plate assist radioactive seeds implantations in in Peking University Third Hospital, and included in the retrospective study. The prescribed dose was 110 -160 Cy. All patients carried out preoperative planning design, individual guide plate production, and compared the dose distribution of postoperative plan with preoperative plan. Dose parameters include D90 , mPD, V100 , V150 , V200 , CI, EI and HI. Statistical method was paired t-test. Results A total of 42 3D printing individual templates were produced. The mean GTV volume of all patients was 28.6 cm^3 , and mean Dgo of postoperative target area （GTV） was 142.6 Gy. For postoperative plans, the mean D90 , mPD, V100 , V150, V200 was 142.6 Gy, 77.3 Gy, 92.48% , 68.40% and 42.98%, respectively, and 144.5 Gy, 70.2 Gy, 91.45%, 63. 12% and 34.74%, respectively, in preoperative plans. Except mPD, V150, V200（t= -2.166, -2.863, -4.778, P〈0.05）, there was no significant difference between the two groups. Conclusions 3D printing guide plate could provide good accuracy for positioning and direction. For local recurrent malignant tumor of head and neck, the actual dose distributions in postoperative validations were close to the expectations of preoperative plans which mean the improvement of accuracy in treatment.