Halcyon和Truebeam加速器平台在直肠癌术后辅助放射治疗中的计划质量及执行效率研究

Study on the plan quality and delivery efficiency of Halcyon and Truebeam accelerator platform in adjuvant radiotherapy after surgery for rectal cancer

目的:研究在直肠癌术后辅助放射治疗中,基于Halcyon和Truebeam两种不同类型医用直线加速器设计的容积旋转调强治疗(VMAT)计划和固定野调强放射治疗(FF-IMRT)计划的计划质量和执行效率差异。方法:采用随机数表法选取在医院接受治疗的18例直肠癌术后患者,基于Halcyon和Truebeam医用直线加速器平台(简称Halcyon平台和Truebeam平台)分别设计VMAT和FF-IMRT计划,比较分析HalcyonVMAT、HalcyonFF-IMRT、TruebeamVMAT和Truebeam FF-IMRT 4种计划的剂量学指标[2%、98%体积受量(D_(2%)、D_(98%)),平均剂量(D_(mean)),10 Gy、20 Gy剂量线覆盖的相对体积(V_(10Gy)、V_(20Gy)),均匀指数(HI),梯度指数(GI)和适形指数(CI)]、机器跳数、执行时间、平均子野面积(MFA)和子野面积变异系数(CVA)等的差异,并进行射野剂量(PD)验证。结果:基于Halcyon平台和Truebeam平台设计的VMAT计划的D2%、GI及CI均优于FF-IMRT计划。两台加速器的VMAT和FF-IMRT共4种计划的靶区D_(2%)、D_(98%)和D_(mean)比较,差异有统计学意义(F=49.429,F=8.515,F=17.216;P<0.05);4种计划的HI、GI和CI比较,差异有统计学意义(F=38.979,F=32.636,F=68.220;P<0.05);4种计划的膀胱剂量指标的V_(10)、V_(20)和D_(mean)相比较,差异有统计学意义(F=15.178,F=13.183,F=8.487;P<0.05);4种计划执行效率的平均机器跳数、平均执行时间差异有统计学意义(F=251.012,F=175.276;P<0.05);HalcyonVMAT计划的复杂度指标MFA和CVA优于TruebeamVMAT计划,4种计划的MFA和CVA相比较差异有统计学意义(F=114.854,F=274.296;P<0.05),4种计划均通过PD验证。结论:在直肠癌辅助放射治疗中,基于Halcyon平台和Truebeam平台设计的VMAT计划相比于FF-IMRT计划均有较好的计划质量和较快的执行效率,Halcyon平台的VMAT计划相比于Truebeam平台的VMAT计划,在满足临床需求的同时能够降低计划的复杂度。

Objective:To study the differences of plan quality and delivery efficiency of volumetric modulated arc therapy(VMAT)and fixed-field intensity-modulated radiation therapy(FF-IMRT)plans based on two kinds of designs of medical linear accelerator(Halcyon and Truebeam)for adjuvant radiotherapy after surgery for rectal cancer.Methods:18 postoperative patients with rectal cancer who received treatment in hospital were randomly selected by random number table method.VMAT plan and FF-IMRT plan were designed respectively based on Halcyon medical linear accelerator platform(Halcyon platform)and Truebeam medical linear accelerator platform(Truebeam platform).The differences of dosimetry indicators[2%volume dose(D_(2%)),98%volume dose(D_(98%)),mean dose(D_(mean)),relative volumes that were covered by 10Gy and 20Gy dose line(V_(10Gy),V_(20Gy)),homogeneity index(HI),gradient index(GI),conformity index(CI)],monitor units(MU),delivery time,mean field area(MFA),coefficient of variation of segments area(CVA)of 4 kinds of plans(VMAT and FF-IMRT of Halcyon platform,VMAT and FF-IMRT of Truebeam)were compared,and the portal dosimetry(PD)of them were verified.Results:The D_(2%),GI,CI of the VMAT plans based on Halcyon platform and Truebeam platform were all superior to FF-IMRT plans of them.The differences of D_(2%),D_(98%)and D_(mean) of target region among 4 kinds of plans were significant(F=49.429,F=8.515,F=17.216,P<0.05).The differences of HI,GI and CI among 4 kinds of plans were significant(F=38.979,F=32.636,F=68.220,P<0.05).The differences of V_(10Gy),V_(20Gy),and D_(mean) of bladder dose indicators among 4 kinds of plans were significant(F=15.178,F=13.183,F=8.487,P<0.05).The differences of average MU and average delivery time of execution efficiencies among 4 kinds of plans were significant(F=251.012,F=175.276,P<0.05).The MFA and CVA of complexity indicator of Halcyon VMAT plan were better than those of Truebeam VMAT plan.And the differences of MFA and CVA among 4 kinds of plans were significant(F=114.854,F=274.296,P<0.05).All 4 plans passed PD verification.Conclusion:In the adjuvant radiotherapy of rectal cancer,the VMAT plans on the basis of Halcyon platform and Truebeam platform have better plan quality and faster delivery efficiency than FF-IMRT plans of them.Compared with VMAT plan of Truebeam platform,VMAT plan of Halcyon platform can reduce the complexity of plan as well as meet the clinical requirement.