非共面与共面模板辅助^(125)粒子植入治疗胰腺癌术前剂量学对比

Preoperative dosimetric comparison between non-coplanar and coplanar template-assisted^(125)I seed implantation for pancreatic cancers

目的比较放射性粒子植入治疗胰腺癌采用非共面和共面模板术前计划参数的差异,以指导临床应用。方法选取2017年1月至2019年5月于北京大学第三医院接受外照射的胰腺癌患者,其影像信息导入近距离治疗计划系统,分别设计非共面计划与共面计划,每例患者处方剂量设定为110 Gy,粒子活度0.4 mCi(1 Ci=3.7×10^10Bq),分别优化剂量分布,比较两者的针数、粒子数、90%和100%靶体积受照剂量(D_(90)、D_(100))、100%、150%、200%的处方剂量覆盖的靶体积(V_(100)、V_(150)、V_(200))、适形指数(CI)、靶区外体积指数(EI)和均匀性指数(HI);比较周围正常器官小肠、结肠、十二指肠、胃、脊髓2 cm^3和5 cm^3所受到的照射剂量D_(2 cm^3)和D_(5 cm^3)。结果共面计划比非共面计划的植入针数18.63 vs.16.45针稍多(t=-3.239,P<0.05);粒子数相当90.2 vs.91.01颗(t=-3.373,P>0.05);靶区的D_(90)、D_(100)、V_(100)、V_(150)、V_(200)、CI、EI、HI差异无统计学意义(P>0.05);周围正常器官小肠、结肠、十二指肠、胃和脊髓的D_(2 cm^3)、D_(5 cm^3)差异无统计学意义(P>0.05)。结论3D打印非共面与共面计划均可达到处方剂量,同时正常器官的剂量相差很小,模板各有自己特点,故临床需要根据具体情况进行选择。

Objective To compare preoperative planning parameters between non-coplanar and coplanar template-assisted radioactive seed implantation in the treatment of pancreatic cancers,in order to guide clinical application.Methods Patients with pancreatic cancers who received external irradiation in the Peking University Third Hospital from Jan 2017 to May 2019 were selected.Their image information was imported into the brachytherapy planning system,and the non-coplanar plan and coplanar plan were designed individually.Each patient's prescription dose was set to 110 Gy,and the activity of the radioactive seeds were 0.4 mCi(1 Ci=3.7×10^10Bq),respectively.For the two plans,the dose distribution was optimized and dosimetric parameters were compared,including the implantation needle number,the implanted seed number,the minimum prescription doses delivered to 90%and 100%of the target volume(D_(90)and D_(100)),mean percentages of volume receiving 100%,150%and 200%of the prescription doses(V_(100),V_(150)and V_(200)),conformity index(CI),external index(EI),and homogeneity index(HI)of the target volume,as well as the doses of 2 cm^3 and 5 cm^3(D_(2 cm^3)and D_(5 cm3^))of the surrounding normal organs such as the small intestines,colon,duodenum,stomach,and spinal cord.Results The implantation needle number in the coplanar plan was slightly higher than that in the non-coplanar plan,namely 18.63 vs.16.45(t=-3.239,P<0.05).The implanted seed number was equivalent,namely 90.2 vs.91.01,with no statistical difference(P>0.05).There was no significant difference between D_(90),D_(100),V_(100),V_(150),V_(200),CI,EI,and HI in the target area of the two plans(P>0.05).Meanwhile,there was no obvious difference in D2 cm3 and D5 cm3 of normal organs including the small intestines,colon,duodenum,stomach,and spinal cord(P>0.05).Conclusions With both the coplanar plan and the non-coplanar plan,the prescription doses can be achieved and meanwhile,there are very small differences in the doses of normal organs.Given that 3D-printing non-coplanar and coplanar templates have their own characteristics,it is necessary to choose them according to specific situations.